In-Cell Touch Line Layout for Uniform Active Matrix Displays
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Solution Overview
Problem
In in-cell touch panels, increasing the number of touch detection lines for finer-resolution touch detection leads to overlapping with data lines, causing capacitance differences and resulting in uneven display performance.
Innovation Solution
The active matrix substrate incorporates touch detection lines with specific portions that overlap and do not overlap source lines, allowing for alternated arrangement to reduce capacitance variations, thereby avoiding uneven display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of touch detection lines is increased for finer-resolution touch detection, then touch detection precision is improved, but capacitance differences occur due to overlapping with data lines, causing display uniformity to deteriorate
Solution Approach 1:
The touch detection line is divided into multiple portions (first portion overlapping source line, second portion not overlapping, third portion connecting them). This segmentation allows different sections to serve different functions: the first portion provides capacitance for detection, the second portion avoids interference with source lines, and the third portion connects them. By alternating the arrangement of second portions in adjacent touch detection lines, the patent achieves uniform capacitance characteristics across all lines, resolving the display uniformity issue while maintaining high touch detection precision through the dedicated first portion for capacitance coupling.
2Device complexity
If touch detection lines are placed to overlap data lines to increase line density, then device integration is improved, but capacitance variations occur, causing potential variations in touch detection electrodes
Solution Approach 1:
Different portions of the touch detection line are assigned different spatial relationships with source lines. The first portion is deliberately placed to overlap source lines to provide necessary capacitance, while the second portion is placed to avoid overlapping source lines to prevent capacitance variations. The third portion connects these two regions. This local differentiation of spatial quality ensures that capacitance-critical sections have proper coupling while other sections avoid interference, maintaining potential stability across all touch detection electrodes.
3Measurement precision
If the number of touch detection lines exceeds the number of data lines, then touch detection resolution is improved, but alternating arrangement becomes necessary, creating capacitance differences between overlapping and non-overlapping lines
Solution Approach 1:
The patent implements a periodic alternating arrangement where the second portion of touch detection lines is alternately positioned relative to source lines in the column direction. Specifically, in odd-numbered columns, second portions are arranged at certain positions, while in even-numbered columns, they are arranged at alternating positions. This periodic pattern ensures that all touch detection lines have equivalent capacitance characteristics despite the increased number of lines, as each line experiences the same average capacitance environment through the alternating pattern.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables an increase in the number of touch detection lines while maintaining even display performance by minimizing capacitance differences and potential variations in touch detection electrode potentials.
Implementation Method 1
This causes a difference between the capacitance of a touch detection line placed over a data line and the capacitance of a touch detection line placed in such a position as not to overlap a data line. Due to this difference in capacitance, there are variations in the potential of a plurality of touch detection electrodes
Data Source
AI summary
An active matrix substrate includes a plurality of source lines and a plurality of touch detection lines. Each of the plurality of touch detection lines includes a first portion and a second portion. The first portion extends along any one of the source lines in such a position as to overlap the source line. The second portion is placed in such a position as not to overlap the plurality of source lines. The second portions of adjacent touch detection lines are alternately arrayed side by side in a direction extending along the source line.